JavaTM 2 Platform Std. Ed. v1.6.0
javax.sound.midi
Class VoiceStatus
java.lang.Object
javax.sound.midi.VoiceStatus
public class VoiceStatus - extends Object
A VoiceStatus object contains information about the current
status of one of the voices produced by a Synthesizer .
MIDI synthesizers are generally capable of producing some maximum number of
simultaneous notes, also referred to as voices. A voice is a stream
of successive single notes, and the process of assigning incoming MIDI notes to
specific voices is known as voice allocation.
However, the voice-allocation algorithm and the contents of each voice are
normally internal to a MIDI synthesizer and hidden from outside view. One can, of
course, learn from MIDI messages which notes the synthesizer is playing, and
one might be able deduce something about the assignment of notes to voices.
But MIDI itself does not provide a means to report which notes a
synthesizer has assigned to which voice, nor even to report how many voices
the synthesizer is capable of synthesizing.
In Java Sound, however, a
Synthesizer class can expose the contents of its voices through its
getVoiceStatus() method.
This behavior is recommended but optional;
synthesizers that don't expose their voice allocation simply return a
zero-length array. A Synthesizer that does report its voice status
should maintain this information at
all times for all of its voices, whether they are currently sounding or
not. In other words, a given type of Synthesizer always has a fixed
number of voices, equal to the maximum number of simultaneous notes it is
capable of sounding.
If the voice is not currently processing a MIDI note, it
is considered inactive. A voice is inactive when it has
been given no note-on commands, or when every note-on command received has
been terminated by a corresponding note-off (or by an "all notes off"
message). For example, this happens when a synthesizer capable of playing 16
simultaneous notes is told to play a four-note chord; only
four voices are active in this case (assuming no earlier notes are still playing).
Usually, a voice whose status is reported as active is producing audible sound, but this
is not always true; it depends on the details of the instrument (that
is, the synthesis algorithm) and how long the note has been going on.
For example, a voice may be synthesizing the sound of a single hand-clap. Because
this sound dies away so quickly, it may become inaudible before a note-off
message is received. In such a situation, the voice is still considered active
even though no sound is currently being produced.
Besides its active or inactive status, the VoiceStatus class
provides fields that reveal the voice's current MIDI channel, bank and
program number, MIDI note number, and MIDI volume. All of these can
change during the course of a voice. While the voice is inactive, each
of these fields has an unspecified value, so you should check the active
field first.
- See Also:
Synthesizer.getMaxPolyphony() ,
Synthesizer.getVoiceStatus()
Field Summary |
boolean |
active
Indicates whether the voice is currently processing a MIDI note. |
int |
bank
The bank number of the instrument that this voice is currently using. |
int |
channel
The MIDI channel on which this voice is playing. |
int |
note
The MIDI note that this voice is playing. |
int |
program
The program number of the instrument that this voice is currently using. |
int |
volume
The current MIDI volume level for the voice. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
active
public boolean active
- Indicates whether the voice is currently processing a MIDI note.
See the explanation of
active and inactive voices.
channel
public int channel
- The MIDI channel on which this voice is playing. The value is a
zero-based channel number if the voice is active, or
unspecified if the voice is inactive.
- See Also:
MidiChannel ,
active
bank
public int bank
- The bank number of the instrument that this voice is currently using.
This is a number dictated by the MIDI bank-select message; it does not
refer to a
SoundBank object.
The value ranges from 0 to 16383 if the voice is active, and is
unspecified if the voice is inactive.
- See Also:
Patch ,
Soundbank ,
active ,
MidiChannel.programChange(int, int)
program
public int program
- The program number of the instrument that this voice is currently using.
The value ranges from 0 to 127 if the voice is active, and is
unspecified if the voice is inactive.
- See Also:
MidiChannel.getProgram() ,
Patch ,
active
note
public int note
- The MIDI note that this voice is playing. The range for an active voice
is from 0 to 127 in semitones, with 60 referring to Middle C.
The value is unspecified if the voice is inactive.
- See Also:
MidiChannel.noteOn(int, int) ,
active
volume
public int volume
- The current MIDI volume level for the voice.
The value ranges from 0 to 127 if the voice is active, and is
unspecified if the voice is inactive.
Note that this value does not necessarily reflect
the instantaneous level of the sound produced by this
voice; that level is the result of many contributing
factors, including the current instrument and the
shape of the amplitude envelope it produces.
- See Also:
active
VoiceStatus
public VoiceStatus()
Copyright 2003 Sun Microsystems, Inc. All rights reserved
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